JDBC练习，查询所有

查询所有数据

1. 获取Connection
2. 定义SQL：selection *from tb_brand;
3. 获取PerparedStatement对象
4. 设置参数：不需要
5. 执行SQL
6. 处理结果：List<Brand>
7. 释放资源

没有系统学过这些，只会套用框架，所以这次我要从涛开始学习，系统学习javaweb，并保证不落下安卓应用开发。

其实也挺简单的，高懂得话就需要一点一点来，全在代码里

package Dutils;

import Bean.Brand;
import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

//品牌数据的增删改查操作
public class text {
    /**
     * 查询所有
     * 1.sql: select *from tb_brand;
     * 2.参数设置
     * 3.结果：List<brand>
     */
    public void TextSelectall() throws Exception {
        //1.获取connect，调用druid连接池
        Properties prop = new Properties();
        prop.load(new FileInputStream("src/druid.properties"));
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);
        Connection conn = dataSource.getConnection();
        //2.定义sql语句
        String sql = "select *from tb_brand";
        //3.获取pstmt对象
        PreparedStatement pstmt = conn.prepareStatement(sql);
        //4.设置参数
                    //查询全部内容不需要设置参数
        //5.执行SQL
        ResultSet rs = pstmt.executeQuery();
        //6.处理结果List<brand> 封装brand,并且把它装载到list这个集合里面去
        Brand brand = null;
        List<Brand> brands = new ArrayList<>();
        while(rs.next()){
            //获取数据
            int Id = rs.getInt("id");
            String BrandName = rs.getString("brand_name");
            String CompanyName = rs.getString("company_name");
            String Ordered = rs.getString("ordered");
            String Description = rs.getString("description");
            int Status = rs.getInt("status");
            //封装Brand
             brand = new Brand();
            brand.setId(Id);
            brand.setBrand_name(BrandName);
            brand.setCompany_name(CompanyName);
            brand.setOrdered(Ordered);
            brand.setDescription(Description);
            brand.setStatus(Status);

            //装载集合
            brands.add(brand);
        }
        System.out.println(brands);
        //7.释放资源
        rs.close();
        pstmt.close();
        conn.close();
    }
}

package Bean;

public class Brand {
    private int id;
    private String brand_name;
    private String company_name;
    private String ordered;
    private String description;
    private int status;


    public Brand() {
    }

    public Brand(int id, String brand_name, String company_name, String ordered, String description, int status) {
        this.id = id;
        this.brand_name = brand_name;
        this.company_name = company_name;
        this.ordered = ordered;
        this.description = description;
        this.status = status;
    }

    /**
     * 获取
     * @return id
     */
    public int getId() {
        return id;
    }

    /**
     * 设置
     * @param id
     */
    public void setId(int id) {
        this.id = id;
    }

    /**
     * 获取
     * @return brand_name
     */
    public String getBrand_name() {
        return brand_name;
    }

    /**
     * 设置
     * @param brand_name
     */
    public void setBrand_name(String brand_name) {
        this.brand_name = brand_name;
    }

    /**
     * 获取
     * @return company_name
     */
    public String getCompany_name() {
        return company_name;
    }

    /**
     * 设置
     * @param company_name
     */
    public void setCompany_name(String company_name) {
        this.company_name = company_name;
    }

    /**
     * 获取
     * @return ordered
     */
    public String getOrdered() {
        return ordered;
    }

    /**
     * 设置
     * @param ordered
     */
    public void setOrdered(String ordered) {
        this.ordered = ordered;
    }

    /**
     * 获取
     * @return description
     */
    public String getDescription() {
        return description;
    }

    /**
     * 设置
     * @param description
     */
    public void setDescription(String description) {
        this.description = description;
    }

    /**
     * 获取
     * @return status
     */
    public int getStatus() {
        return status;
    }

    /**
     * 设置
     * @param status
     */
    public void setStatus(int status) {
        this.status = status;
    }

    public String toString() {
        return "Bean{id = " + id + ", brand_name = " + brand_name + ", company_name = " + company_name + ", ordered = " + ordered + ", description = " + description + ", status = " + status + "}";
    }
}